# Illustration Photons of different energy, frequency and wavelength

Photons are "light particles" which have a certain energy $$W_{\text p }$$ (called photon energy). How large this energy is depends on the frequency $$f$$ or the wavelength $$\lambda$$ of the light used:$$W_{\text p } ~=~ h \, f ~=~ h \, \frac{c}{\lambda}$$
Here $$h$$ is the Planck's constant with the value: $$h ~=~ 6.626 \cdot 10^{-34} \, \mathrm{Js}$$And $$c$$ the speed of light with the value:$$c ~=~ 3 \cdot 10^8 \, \frac{\mathrm m}{\mathrm s}$$